Engineering Lab - Automatic Control Systems (MATLAB & Simulink)

INSTITUTIONAL AFFILIATION
FACULTY OR DEPARTMENT
COURSE ID & NAME
TITLE: ENGINEERING LAB- AUTOMATIC CONTROL SYSTEMS (MATLAB &
SIMULINK)
STUDENT NAME
STUDENT ID NUMBER
PROFESSOR (TUTOR)
DATE OF SUBMISSION
2018

Patient lift Simulink model,
1
Add
60
Kp Add1
20
1/ L
1
s
Int egrator
0.084
Ke
3
R
Add2
1/93
GearBox
0.05
Pulley
1
s
Int egrator1
1
s
Int egrator2
9.8
Constant
Add3
100
Weight
Add4
0.05
Pulley1
1/93
Gearbox1
Product
14
WeightDisturbance
Step
1
s
Int egrator3
1e-5
Gain10
1.2e4
Gain11
0.084
Gain12
0.5
Gain13
0.5
Gain14
Add5
1
Desired Height
1
Out1
InputOutput
Accelerometer

TASK 1
Analysis of the lift in s-domain and the frequency domain
Step 1: Stability
Creating a subsystem of the model above,
Desired Height Out1
patient_lift
Scopedesired height
PID(s)
Control_point
Linearizing the system, we obtain,
>> mdl='order750864'
>> open_system(mdl)
>> io(1)=linio('order750864/Control_point',1,'input');
>> io(2)=linio('order750864/patient_lift',1,'openoutput');
>> %% To linearise the model
>> linsys1=linearize(mdl,io)
Analyzing the response of the linearized model using the bode response,
2

-200
-150
-100
-50
0
Magnitude (dB)
From: Controlpoint To: patient lift
10-15 10-10 10-5 100
-270
-180
-90
0
Phase (deg)
Bode Diagram
Frequency (rad/s)
Figure 1 For an unstable system, before kp is set
To determine the system stability of the closed loop system,
3